Investigation on Dielectric Permittivity of PZT Manufactured by Electric Field Assisted Sintering

Abstract

By using submicron PZT(Pb[Zrx,Ti1-x]O3 (0≤x≤1)) materials system, we provided electric field assisted sintering at 482–520 oC temperature range in conjunction with 60 V/mm dc electric field on the specimen. The furnace temperature increased up to 520 oC with 10 oC/min increment. 0.3 amp current cut off was set by dc power supply to eliminate further temperature increase on specimen due to joule heating. The electric field assisted sintering system was prepared with sandwich type experimental setup. The specimen showing initially insulator behavior, revealed current leakage at 482 oC. Maximum current draw of 0.3 amp was reached at 502 oC with total power absorption of 5.27 watt/mm3 during whole experiment. The power supply spontaneously decreased the electric field 20 V/cm due to variation conductivity behavior of specimen and maximum current cut off. Reaching 95 % theoretical density was verified with FESEM micrograph and there is almost no grain growth on specimen except very good grain boundary generation. The sintered PZT specimen showed appreciable dielectric permittivity (εr =273) on 1 kHz at room temperature comparing with other studies. Total power absorption of 5.27 watt/mm3 in 180 seconds decreased sintering temperature from 1200 oC to 500 oC. Such an effect cannot be explained with joule heating in a short period of time with very low power supply. Therefore, we ascribe this behavior to electric field related polarization of atoms rested in lattice which increases mass transport triggered with impulse electron flux thorough electric field. Thermodiffusion (Soret effect) and electromigration are few theories could explain this phenomena. With this low temperature sintering techniques, lead emission could also be restricted during manufacturing process.